Feb., 1951
COMMUNICATIONS TO THE EDITOR
by the report that isopropyl hydroperoxide, which is relatively stable to acidic and neutral solutions, under alkaline conditions rapidly gives acetone. Similarly, peroxides and hydroperoxides such as ipropyl-t-butyl peroxide and cyclohexene hydroperoxide will be expected to exhibit instability toward bases.4 The base-catalyzed decompositions of peroxides and hydroperoxides apparently exemplify a rather general type of elimination reaction which may be anticipated for compounds in which an atom or group X, capable of giving a relatively stable anion X-, is attached to oxygen
881 NHBz
"2
I
I
H
H
I
I1
hours yielded the dihydrochloride of an optically inactive diacidic base. Anal. Calcd. for C6H1,NzO3.2HCI: C, 30.66; H, 6.86; N, 11.93; C1, R' 30.17; eq. wt., 117.5. Found: C, 30.89; H, I 6.71; N, 12.19; C1, 29.44; eq. wt., 120 (potentio:Base R-C-0-X + I metric titration). Benzoylation of this base gave a H pentabenzoate. Anal. Calcd. for C6HyN203R' (COH~CO)~: C, 72.12; H, 5.02; N, 4.10. Found: C, 71.77; H, 5.05; N, 4.04. Selective oxygen-deR-LO XH:Base (4) benzoylation of the pentabenzoate with barium Thus the decompositionof nitrate esters (X = -NO2) methoxide in methanol yielded an N,N'-dibenzoyl under the influence of hydroxide ion is an analo- derivative. Anal. Calcd. for C ~ H ~ ~ O ~ ( C ~ H S gous process; HOC~H6-cH+--N02f' 4 C0)2: C, 64.85; H, 5.99; N, 7.55. Found: C, 65.05; H, 5.90; N, 7.70. -l H The original free base consumed four moles of CBH&H=O NO2- iH20.5 To test the periodate whereas its N,N'-dibenzoyl derivative generality of reaction (4) the following suggest utilized two moles. These combined data sugthemselves for study: X = C(C6HS)3,NR2, mesi- gested that the structure of the base was that of a toyl, -kC-Aryl, etc.'j 1,3-diamino-4,5,6-trihydroxycyclohexane (I). Peroxide I was obtained by the action of potasConfirmation of structure I was obtained by the sium t-butyl peroxide on 1-phenylethyl bromide; following series of reactions and products. Periob.p. 56-3-57' (1.3 mm.); n2'D 1.4809 (calcd. for date oxidation of the N,N'-dibenzoyl derivative C12Hls02: C, 74.18; H, 9.34. Found: C, 74.35, yielded a dialdehyde, which was not separated, but 74.51; H, 9.18, 9.14). When I (0.08 mole) was which upon treatment with ethyl mercaptan and dissolved in piperidine (0.40 mole) the temperature hydrogen chloride gave a dimercaptal; m.p. 140rose to 50' within fifteen minutes. At this point 141'. Anal. Calcd. for CI~H~~N&(CBH&!O)~ : C, the solution was cooled to 25' and then maintained 58.87; H, 6.95; N, 5.09; S, 23.3. Found: C, at 25' for eighty hours. Acetophenone was iso- 58.97; H, 6.91; N, 5.40; S, 23.8. The dimercaplated in 79% yield; t-butyl alcohol, in 25% yield. tal was converted by hydrogenolysis with Raney When 0.05 mole I was mixed with 0.01 mole piperi- nickel to an N,N'-dibenzamido-pentane (11); m.p. dine the temperature did not rise; after eighty- 197-197.5'. Anal. Calcd. for C1sHzzNzO2: C, four hours at 25', a 32% yield of acetophenone was 73.55; H, 7.10; N, 9.03. Found: C, 73.53; H, obtained. 6.96; N, 8.50. The higher-melting meso isomer2 of 1,3-dibenza(3) S.S. Medwedew and E. Alexejewa, Ber., 65, 133 (1932). mido-pentane was prepared by stepwise catalytic (4) Compare V. L.Vaiser, C. A . , 44, 3446 (1950); F.F.Rust, F. H. Seubold, and W. E. Vaughan, THIS JOURNAL, 79, 338 (1950). reduction and benzoylation of acetylacetone diox(5) J. W.Baker and D. M. Easty, Nature, 166, 156 (1950). ime. It melted a t 197.5-198', and caused no de(6) The base-catalyzed decomposition of hypohalites bas been formulated as in eq. 4; X = Cl. Private communication from Dr. pression of melting point upon admixture with the Saul Winstein. degradation product.
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+
+
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DEPARTMENT OF CHEMISTRY PURDUIE UNIVERSITY NATHAN KORNBLUM LAFAYETTE, INDIANA HAROLD E. DELAMARE RECEIVED DECEMBER 1, 1950 STREPTOMYCES ANTIBIOTICS. XXIII.
NH2
H 1
I
1,3-DI-
AMINO-4,5,6-TRIHYDROXYCYCLOHEXANE FROM NEOMYCIN A.
Sir: Neomycin A has been degraded to a new compound which has been established as a meso form of 1,3-diamino-4,5,6-trihydroxycyclohexane (I). Hydrolysis of Neomycin A' by heating a solution of it in 6 N hydrochloric acid at 140' for sixteen (1) Peck, Hofine, (1949).
Gale and Folkers, THISJOURNAL.
. 71.. 2590
H
OH rII
The nitrogen atoms of this meso isomer of 1,3-diamino-4,5,6-trihydroxycyclohexane must have a cis relationship, and if the molecule is biogenetically related to streptidine, which has an all-trans(2) Dippel, &e. t ~ a vchim., . 60,525 (1931).
582
COMMUNICATIONS TO THE EDITOR
configuration,3 its configuration would be all-trans also (111).
Vol. 73
tors, and the mechanism of the above reaction, are under investigation.
L. H. SOWER (3) Wolfrom and Olin, THIS JOURNAL, 72, 1724 (1950). N. S MARANS THEWHITMORE LABORATORY RESEARCH LABORATORIES FREDERICK A. KUEHL,JR. THEPENNSYLVANIA STATE COLLEGE G. M. GOLDBERG MERCK& Co., INC. MARYNEALEBISHOP STATECOLLEGE, PA. J. ROCKETT RAHWAY, N. J. KARLFOLKERS R. P. PIOCH RECEIVED JANUARY 4, 1951 RECEIVED DECEMBER 18, 1950 A NEW REACTION IN ORGANOSILICON CHEMISTRY Sir :
We wish to report a new reaction which proceeds readily with certain organosilicon structures in the presence of concentrated sulfuric acid and involves cleavage of one methyl group from trimethylsilyl, Me3Si, in a variety of compounds containing functional groups linked to carbon. This reaction makes possible the synthesis of a large number of hitherto unavailable new-type organosiloxanes. p-Trimethylsilylpropionic acid2 (294 g.) was added dropwise with stirring to 400 cc. of cold (10') concentrated sulfuric acid during one and one-half hours. A vigorous evolution of methane (identified by infrared absorption spectrum) occurred during the addition. Reaction was completed by warming on the steam-bath for one hour until gas evolution ceased. The reaction mixture was cooled and poured onto cracked ice, giving immediate formation of a white solid. Recrystallization from nhexane gave 265 g., 95% yield, of 4,4,6,6-tetramethyl-4,6-disila-5-oxanonanedioicacid, m.p. 5354'. Anal. CloH&iaOa: Si, 20.16; neut. equiv., 139. Found: Si, 20.02; neut. equiv., 140.
LIGHT SCATTERING STUDIES ON FIBRINOGEN: PRELIMINARY REMARKS Sir :
In view of the wide interest appertaining to the fibrinogen-fibrin system and the numerous workers currently engaged upon it, we wish to present here some pertinent results obtained by the light scattering m e t h ~ d . ~ J JThese * ~ results will also be reported in greater length and detail later. Fibrinogen was prepared by fractionation of Armour plasma fraction I.4 A product was obtained which displayed only a single boundary in the ultracentrifuge and with a minimum of 95% polymerizable protein. Measurements upon three different samples at p H ' s 8.40 and 7.00 a t ionic strength 0.35 gave for the native fibrinogen an average molecular weight of 540,000 and a length from the extrapolated dissymmetry coefficient of 850A. It is apparent that the fibrinogen molecule is an asymmetric, rod-like particle. The addition of thrombin to an activity of about 0.1 unit/ml. to a 0.14% solution of fibrinogen at PH 8.40 and ionic strength 0.35 brought about a rapid increase in dissymetry and turbidity. The increase HzSOc HzO in length calculated from the dissymetry was lin2 MeaSiCHzCHZCOzH + -+ ear in time throughout the early stages of the reac(H20CCHzCH2SiMe2)*0 2 CH, tion. A comparison of the average degrees of polyReaction of P-trimethylsilylethylamine, MeaSiCH2- merization calculated from the increase in length of CH2NH2, with concentrated sulfuric acid by the fibrinogen molecules as well as end to end associaprocedure described above, followed by treatment tion occurred. with base, gave a 76% yield of 1,7-diamino-3,3,5,5Prior to gelation under these conditions the distetramethyl-3,5-disila-4-oxa-heptane, ("&Hasymmetry coefficient did not increase beyond the CH2SiMe2)20, b.p. 115' (13 m r n . ) , n Z 01.4473. ~ limiting value for a rod-like molecule. At a time Anal. CsH24Si2N20: Si, 25.51. Found: Si, 25.46. immediately preceding gelation the weight average Similarly, reaction of 4-trimethylsilyl-2-buta- molecular weight was about 4,000,000 and the avnonej4 Me3SiCH2CH&OCHs, with concentrated erage length about 2500 A. It was indicated that sulfuric acid, followed by treatment with water, rod-like units averaging about three times the gave 42% yield of 5,5,7,7-tetramethyl-5,7-disila-6-length of native fibrinogen and about eight times its oxa-2,10-undecanedione,(CH3COCH2CH2SiMe&0, molecular weight exist in solution prior to gelation b.p. 142' (6 mm.), n% 1.4390. Anal. C12- under these conditions. H26SizOa: Si, 20.46; mol. wt., 274. Found: Si, After gelation a slow increase in both turbidity 20.60; mol. wt., 283. and dissymmetry occurs. The process a t @H7.00 The general scope, definitive constitutional fac- with other conditions unchanged is qualitatively quite similar except that after gelation the turbid(1) It is, of course, important to recognize that organosilicon structures capable of yielding a 8-carbonmm ion (MeaSi-C-C+) with ity of the gel increased to a slightly higher value concentrated sulfuric acid will give cleavage of the organic group conthan a t pH 8.40. taining the functional group, and hence cannot undergo the above The action of papain is qualitatively similar to reaction. cf P. C. Whitmore. L. H. Sommer, J. Gold and R. E. Van that of thrombin in producing a gel. The hydroStrien, THISJOURNAL, 69, 1551 (1947); L. H Sommer, L. J. Tyler and F. C. Whitmore, ibid., 70,2872 (1948), J. Gold, L.H. Sommer and lytic action of the papain slowly dissolved the gel F. C. Whitmore, ibid., 70, 2874 (1948). formed, yielding eventually a product of a weight (2) L. H. Sommer, J. Gold, G. M Goldberg and N. S. Marans, average molecular weight 200,000. ibid., 71, 1509 (1949).
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(3) 8-Trimethylsilylethylamiae,b.p. 121' (734 mm.), n * * 1.4241, ~ Si, 24.06% (calcd. 23.931, was prepared by the Hofmann reaction from 6-trimethylsilylpmpionamide, m.p. 95-96O, Si, 19.43% (calcd. 19.31); which was in turn prepared from ~-trimethylsilylpropioaylchloride, tJ p. 92' (65 mm.), Si, 16.84% (calcd. 17.03). The latter resulted from treatment of 8-trimethylsilylpropionic acid* with thionyl chloride. (4) 1.. H. Sommer and N. S. Marans. ibid., 72, 1935 (1960).
(1) I. T. Edsall, J. F. Foster and H. Scheinberg, THIS JOWRNAL, 69, 2731 (1947). (2) J. L. Oncley, G. Scatchard and A. Brown, J . Phys. Colloid Chem., 21, 184 (1947). (3) K.Laki, Sludres Insl. M i d . Chem. Unio. Sacged, I,27 (1942). (4) FL Laki, to be published. (5) J. D. Ferry and P. R. Morrison, THISJOURNAL, 69,388 (1947).
